Wireless communication method and apparatus for preventing network access by mobile stations which support an incompatible internet protocol version

ABSTRACT

A method and apparatus for determining whether attach procedures between a wireless transmit/receive unit (WTRU) and a network should proceed based on whether the internet protocol (IP) version, (i.e., packet data protocol (PDP) type), of the WTRU is compatible with the network. In one embodiment, the WTRU receives a network compatibility message from the network which indicates the network&#39;s IP version. If the network&#39;s IP version is determined by the WTRU to be compatible, the WTRU and the network proceed with the attach procedures. In another embodiment, the network receives an attach request message from the WTRU which indicates the IP version of the WTRU. If the IP version of the WTRU is determined by the network to be compatible, the network and the WTRU proceed with the attach procedures. For both embodiments, another network is selected if the IP versions of the WTRU and the network are not compatible.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No.60/592,872, filed Jul. 30, 2004, which is incorporated by reference asif fully set forth herein.

FIELD OF INVENTION

The present invention is related to a wireless communication systemincluding at least one communication network, (such as a serving generalpacket radio service (GPRS) support node (SGSN) or a public land mobilenetwork (PLMN)), and at least one wireless transmit/receive unit (WTRU),each supporting a particular internet protocol (IP) version, (i.e.,packet data protocol (PDP) type), used to establish IP connectivity,(i.e., PDP context). More particularly, the wireless communicationsystem prevents the WTRU from accessing services provided by a networkhaving an IP version that is not supported by the WTRU.

BACKGROUND

In conventional wireless communication systems, a WTRU can attach to anynetwork regardless of the IP version that the WTRU supports. However, inorder to establish IP connectivity, (i.e., PDP context), the IP versionof the WTRU must be compatible with the IP version supported by thenetwork. The network may include a Node-B which supports the same IPversion as the network.

If the IP versions of the WTRU and the network are not compatible, thePDP context will be rejected, causing the WTRU to be denied IPmultimedia subsystem (IMS) based services after a considerable delayperiod.

For example, the standard, (TS 23.221), mandates that a Third GenerationPartnership Project (3GPP) IP Multimedia Subsystem (IMS) exclusivelyoperates according to IP version 6 (v6). However, there will be an IPversion 4 (v4) based IMS implementation for GPRS networks, and the 3GPP2IMS is based on IP v4.

Hence, there is a need for the interworking between different versionsof IMSs. A wireless communication method and system for reducing networksearch time and unnecessary traffic by barring IP incompatible WTRUsfrom accessing the network is desired.

SUMMARY

The present invention is a method and apparatus for determining whetherattach procedures between a WTRU and a network should proceed based onwhether the IP version, (i.e., PDP type), of the WTRU is compatible withthe network. In one embodiment, the WTRU receives a networkcompatibility message from the network which indicates the network's IPversion. If the network's IP version is determined by the WTRU to becompatible, the WTRU and the network proceed with the attach procedures.In another embodiment, the network receives an attach request messagefrom the WTRU which indicates the IP version of the WTRU. If the IPversion of the WTRU is determined by the network to be compatible, thenetwork and the WTRU proceed with the attach procedures. For bothembodiments, another network is selected if the IP versions of the WTRUand the network are not compatible.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding of the invention may be had from thefollowing description of a preferred embodiment, given by way ofexample, and to be understood in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a block diagram of a wireless communication system including aWTRU which receives a message from at least one network over a broadcastchannel indicating an IP version that the network supports in accordancewith one embodiment of the present invention;

FIG. 2 is a block diagram of a wireless communication system including aWTRU which transmits an attach request message to at least one networkindicating an IP version that the WTRU supports in accordance withanother embodiment of the present invention;

FIG. 3 is a flow diagram of a process including method steps implementedby the wireless communication system of FIG. 1;

FIG. 4 is a flow diagram of a process including method steps implementedby the wireless communication system of FIG. 2;

FIG. 5 is a block diagram of a WTRU used to implement the process ofFIG. 3 in the system of FIG. 1; and

FIG. 6 is a block diagram of a Node-B/network used to implement theprocess of FIG. 4 in the system of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereafter, the terminology “WTRU” includes but is not limited to a userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, or any other type of device capable of operating in a wirelessenvironment. When referred to hereafter, the terminology “Node-B”includes but is not limited to a base station, a site controller, anaccess point or any other type of interfacing device in a wirelessenvironment.

The features of the present invention may be incorporated into anintegrated circuit (IC) or be configured in a circuit comprising amultitude of interconnecting components.

FIG. 1 is a block diagram of a wireless communication system 100including a WTRU 105 which receives a network capability message 120,125 from at least one network 110, 115 over a broadcast channelindicating a particular IP version that the network 110, 115 supports inaccordance with one embodiment of the present invention. The network110, 115 may include a Node-B (not shown) which supports the same IPversion as the network 110, 115.

FIG. 2 is a block diagram of a wireless communication system 200including a WTRU 105′ which transmits an attach request message 205, 210to at least one network 110′, 115′ indicating an IP version that theWTRU 105′ supports in accordance with another embodiment of the presentinvention. The network 110′, 115′ may include a Node-B (not shown) whichsupports the same IP version as the network 110′, 115′.

FIG. 3 is a flow diagram of a process 300 including method stepsimplemented by the wireless communication system 100. Referring to FIGS.1 and 3, when the WTRU 105 powers up (step 305), the WTRU 105 scans fora control channel (step 310) and tunes in and listens to a firstbroadcast channel in the control channel associated with a first network110 (step 315). The WTRU 105 receives a network capability message 120sent by the first network 110 over the first broadcast channelindicating a particular IP version, (i.e., PDP type), supported by thefirst network 110 (step 320). The network capability message 120 mayinclude a field having two (2) bits which represent a PDP type. Forexample, a field having a PDP type “00” may indicate that the firstnetwork 110 supports IP version 4, a field having a PDP type “01” mayindicate that the first network 110 supports IP version 6, and a fieldhaving a PDP type “10” may indicate that the first network 110 supportsboth IP version 4 and IP version 6.

In step 325, the WTRU 105 determines whether the IP version of the firstnetwork 110 indicated in the network capability message 120 is the sameas the IP version supported by the WTRU 105 (step 325).

If the IP version of the WTRU 105 is determined by the WTRU 105 not tobe the same as, (i.e., is not compatible with), the IP version of thefirst network 110, the WTRU 105 selects a second network 115, (i.e.,tunes in and listen to a second broadcast channel associated with thesecond network 115), in step 330, and the WTRU 105 receives a networkcapability message 125 sent by the second network 115 over the secondbroadcast channel indicating a particular IP version, (i.e., PDP type),supported by the second network 115 (step 320).

In one embodiment, the WTRU 105 may be directed by the first network 110to select the second network 115, wherein the first network 110 hasknowledge of another network that is compatible with the IP version ofthe WTRU 105. Alternatively, the first network 110 may broadcast a listof neighboring networks in an attempt to assist the WTRU 105 in findinga network that serves the same general area as the first network 110.

In another embodiment, the WTRU 105 may include a memory that stores alist of network identifiers. The WTRU 105 may scan the control channel,monitor a plurality of network broadcast channels and select a networkhaving an identifier that matches one of the identifiers in the memoryof the WTRU 105. If more than one match occurs, the WTRU 105 may rely onadditional priority information stored in the memory that dictates apreference to select the network having the highest priority. If a matchdoes not occur, the WTRU 105 continues to scan the control channel.

If the IP version of the first network 110 or the second network 115 isdetermined in step 325 by the WTRU 105 to be the same as, (compatiblewith), the IP version of the WTRU 105, the compatible network 110 or 115and the WTRU 105 proceed with implementing attach procedures 130, (i.e.,registration), to establish a communication link between the WTRU 105and the compatible network 110 or 115.

FIG. 4 is a flow diagram of a process 400 including method stepsimplemented by the wireless communication system 200. Referring to FIGS.2 and 4, when the WTRU 105′ powers up (step 405), the WTRU 105′ scansfor a control channel (step 410) and tunes in and listens to a firstbroadcast channel in the control channel associated with a first network110′ (step 415). The WTRU 105′ sends an attach request message 205 overthe broadcast channel indicating a particular IP version, (i.e., PDPtype), supported by the WTRU 105′ to the first network 110′ (step 420).The attach request message 205 may include a field having two (2) bitswhich represent a PDP type. For example, a field having a PDP type “00”may indicate that the WTRU 105′ supports IP version 4, a field having aPDP type “01” may indicate that the WTRU 105′ supports IP version 6, anda field having a PDP type “10” may indicate that the WTRU 105′ supportsboth IP version 4 and IP version 6.

In step 425, the first network 110′ receives the attach request message205 from the WTRU 105′ (step 425) and determines whether the IP versionof the WTRU 105′ indicated in the attach request message 205 is the sameas the IP version supported by the first network 110′ (step 430).

If the IP version of the WTRU 105′ is determined by the first network110′ not to be the same as, (i.e., is not compatible with), the IPversion of the first network 110,′ the network 110′ sends a message 215to the WTRU 105′ indicating that the attach request has been denied(step 435). The WTRU 105′ then tunes in and listens to a secondbroadcast channel associated with a second network 115′ in step 440. TheWTRU 105′ may be directed by the first network 110′ to select the secondnetwork 115′, wherein the first network 110′ has knowledge of anothernetwork that is compatible with the IP version of the WTRU 105′.

In one embodiment, the WTRU 105′ may be directed by the first network110′ to select the second network 115′, wherein the first network 110′has knowledge of another network that is compatible with the IP versionof the WTRU 105′. Alternatively, the first network 110′ may broadcast alist of neighboring networks in an attempt to assist the WTRU 105′ infinding a network that serves the same general area as the first network110′.

In another embodiment, the WTRU 105′ may include a memory that stores alist of network identifiers. The WTRU 105′ may scan the control channel,monitor a plurality of network broadcast channels and select a networkhaving an identifier that matches one of the identifiers in the memoryof the WTRU 105′. If more than one match occurs, the WTRU 105′ may relyon additional priority information stored in the memory that dictates apreference to select the network having the highest priority. If a matchdoes not occur, the WTRU 105′ continues to scan the control channel.

If the IP version of the WTRU 105′ is determined in step 430 by thenetwork 110′ or the network 115′ to be network compatible, the WTRU 105′and the compatible network 110′ or 115′ proceed with attach procedures220, (i.e., registration), to establish a communication link between theWTRU 105′ and the compatible network 110′ or 115′ (step 445).

FIG. 5 is a block diagram of a WTRU 500 used to implement the process300 in the wireless communication system 100. The WTRU 500 includes anantenna 505, a receiver 510, a transmitter 515, a processor 520 and amemory 525. When the WTRU 500 powers up, the receiver 510 scans for acontrol channel via the antenna 505, and tunes in and listens to a firstbroadcast channel in the control channel associated with a first network110. The receiver 510 receives a network compatibility message 120 sentby the first network 110 over the first broadcast channel indicating aparticular IP version, (i.e., PDP type), supported by the first network110. The receiver 510 forwards the network compatibility message 120 tothe processor 520 which compares the particular IP version supported bythe first network 110 with data, stored in the memory 525, whichindicates the IP version of the WTRU 500.

If the processor 520 determines that the IP version of the WTRU 500 isnot the same as, (i.e., is not compatible with), the IP version of thefirst network 110, the processor 520 controls the receiver 510 such thatit tunes in and listens to a second broadcast channel associated with asecond network 115. The receiver 510 receives a network compatibilitymessage 125 sent by the second network 115 over the second broadcastchannel indicating a particular IP version, (i.e., PDP type), supportedby the second network.

If the IP version of the WTRU 500 is determined by the processor 520 tobe the same as, (i.e., compatible with), the IP version of the firstnetwork 110 or the second network 115, the receiver 510, the processor520, the memory 525 and the transmitter 515 are used to proceed withimplementing attach procedures 130, (i.e., registration), to establish acommunication link between the WTRU 500 and the compatible network 110,115.

FIG. 6 is a block diagram of a Node-B/network 600 used to implement theprocess 400 in the wireless communication system 200. The Node-B/network600 includes an antenna 605, a receiver 610, a transmitter 615, aprocessor 620 and a memory 625. The receiver 610 receives an attachrequest message 205 from the WTRU 105′ over the broadcast channel viathe antenna 605. The attach request message 205 indicates a particularIP version, (i.e., PDP type), supported by the WTRU 105′. The receiver610 forwards the attach request message 205 to the processor 620 whichcompares the particular IP version supported by the WTRU 105′ with data,stored in the memory 625, which indicates the IP version of theNode-B/network 600.

If the processor 620 determines that the IP version of theNode-B/network 600 is not the same as, (i.e., is not compatible with),the IP version of the WTRU 105′, the processor 620 controls thetransmitter 615 to send a message 215 indicating that the attach requesthas been denied.

If the IP version of the WTRU 105′ is determined by the processor 620 tobe the same as, (i.e., compatible with), the IP version of theNode-B/network 600, the receiver 610, the processor 620, the memory 625and the transmitter 615 are used to proceed with implementing attachprocedures, (i.e., registration), to establish a communication linkbetween the WTRU 105′ and the Node-B/network 600.

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone (without the other features andelements of the preferred embodiments) or in various combinations withor without other features and elements of the present invention.

1. In a wireless communication system including at least one networkwhich supports a first internet protocol (IP) version and at least onewireless transmit/receive unit (WTRU) which supports a second IPversion, a method of determining whether attach procedures between thenetwork and the WTRU should be implemented based on IP versioncompatibility, the method comprising: (a) the WTRU tuning to andmonitoring a first broadcast channel; (b) the WTRU receiving a firstnetwork compatibility message from a first network associated with thefirst broadcast channel which indicates the first IP version; (c) theWTRU determining whether the first IP version of the first network iscompatible with the second IP version of the WTRU; and (d) if the firstand second IP versions are determined by the WTRU to be compatible,proceeding with the attach procedures to establish a communication linkbetween the WTRU and the first network.
 2. The method of claim 1 whereinthe first network includes a serving general packet radio service (GPRS)support node (SGSN).
 3. The method of claim 1 further comprising: (e)the WTRU tuning to and monitoring a second broadcast channel if thefirst and second IP versions are determined by the WTRU not to becompatible; (f) the WTRU receiving a second network compatibilitymessage from a second network associated with the second broadcastchannel which indicates a third IP version; and (g) if the first andthird IP versions are determined by the WTRU to be compatible,proceeding with the attach procedures to establish a communication linkbetween the WTRU and the second network.
 4. The method of claim 3wherein the second network is a public land mobile network (PLMN). 5.The method of claim 3 wherein the first network directs the WTRU toattempt to establish a communication link with the second network. 6.The method of claim 1 wherein the first network compatibility messageincludes a field having a packet data protocol (PDP) type.
 7. The methodof claim 6 wherein the PDP type is represented by two bits “00”indicating that the network supports IP version
 4. 8. The method ofclaim 6 wherein the PDP type is represented by two bits “01” indicatingthat the network supports IP version
 6. 9. The method of claim 6 whereinthe PDP type is represented by two bits “10” indicating that the networksupports both IP version 4 and IP version
 6. 10. The method of claim 3wherein the second network compatibility message includes a field havinga packet data protocol (PDP) type.
 11. The method of claim 10 whereinthe PDP type is represented by two bits “00” indicating that the networksupports IP version
 4. 12. The method of claim 10 wherein the PDP typeis represented by two bits “01” indicating that the network supports IPversion
 6. 13. The method of claim 10 wherein the PDP type isrepresented by two bits “10” indicating that the network supports bothIP version 4 and IP version
 6. 14. In a wireless communication systemincluding at least one wireless transmit/receive unit (WTRU) whichsupports a first internet protocol (IP) version and at least one networkwhich supports a second IP version, a method of determining whetherattach procedures between the network and the WTRU should be implementedbased on IP version compatibility, the method comprising: (a) the WTRUtuning to and monitoring a first broadcast channel; (b) the WTRU sendinga first attach request message to a first network associated with thefirst broadcast channel which indicates the first IP version; (c) thefirst network determining whether the first IP version of the WTRU iscompatible with the second IP version of the first network; and (d) ifthe first and second IP versions are determined by the first network tobe compatible, proceeding with the attach procedures to establish acommunication link between the first network and the WTRU.
 15. Themethod of claim 14 wherein the first network includes a serving generalpacket radio service (GPRS) support node (SGSN).
 16. The method of claim14 wherein if the first and second IP versions are determined by thefirst network not to be compatible, the method further comprises: (e)the first network sending a message to the WTRU indicating that theattach request has been denied; (f) the WTRU tuning to and monitoring asecond broadcast channel in response to receiving the message of step(e); (g) the WTRU sending a second attach request message whichindicates the first IP version to a second network which supports athird IP version, the second network being associated with the secondbroadcast channel; and (h) if the first and third IP versions aredetermined by the second network to be compatible, proceeding with theattach procedures to establish a communication link between the secondnetwork and the WTRU.
 17. The method of claim 16 wherein the secondnetwork is a public land mobile network (PLMN).
 18. The method of claim16 wherein the first network directs the WTRU to attempt to establish acommunication link with the second network.
 19. The method of claim 14wherein the first attach request message includes a field having apacket data protocol (PDP) type.
 20. The method of claim 19 wherein thePDP type is represented by two bits “00” indicating that the networksupports IP version
 4. 21. The method of claim 19 wherein the PDP typeis represented by two bits “01” indicating that the network supports IPversion
 6. 22. The method of claim 19 wherein the PDP type isrepresented by two bits “10” indicating that the network supports bothIP version 4 and IP version
 6. 23. The method of claim 16 wherein thesecond attach request message includes a field having a packet dataprotocol (PDP) type.
 24. The method of claim 23 wherein the PDP type isrepresented by two bits “00” indicating that the network supports IPversion
 4. 25. The method of claim 23 wherein the PDP type isrepresented by two bits “01” indicating that the network supports IPversion
 6. 26. The method of claim 23 wherein the PDP type isrepresented by two bits “10” indicating that the network supports bothIP version 4 and IP version
 6. 27. A wireless communication system fordetermining whether attach procedures should be implemented based oninternet protocol (IP) version compatibility, the system comprising: (a)a first network which supports a first IP version; and (b) at least onewireless transmit/receive unit (WTRU) which supports a second IPversion, wherein the WTRU receives a first network compatibility messagefrom the first network which indicates the first IP version and, if thefirst and second IP versions are determined by the WTRU to becompatible, the WTRU and the first network proceed with the attachprocedures to establish a communication link between the WTRU and thefirst network.
 28. The system of claim 27 wherein the first networkincludes a serving general packet radio service (GPRS) support node(SGSN).
 29. The system of claim 27 wherein if the first and second IPversions are determined by the WTRU not to be compatible, the WTRUreceives a second network compatibility message from a second networkwhich indicates a third IP version and, if the first and third IPversions are determined by the WTRU to be compatible, the WTRU and thefirst network proceed with the attach procedures to establish acommunication link between the WTRU and the second network.
 30. Thesystem of claim 29 wherein the second network is a public land mobilenetwork (PLMN).
 31. The system of claim 28 wherein the first networkdirects the WTRU to attempt to establish a communication link with thesecond network.
 32. The system of claim 27 wherein the first networkcompatibility message includes a field having a packet data protocol(PDP) type.
 33. The system of claim 32 wherein the PDP type isrepresented by two bits “00” indicating that the network supports IPversion
 4. 34. The system of claim 32 wherein the PDP type isrepresented by two bits “01” indicating that the network supports IPversion
 6. 35. The system of claim 32 wherein the PDP type isrepresented by two bits “10” indicating that the network supports bothIP version 4 and IP version
 6. 36. The system of claim 29 wherein thesecond network compatibility message includes a field having a packetdata protocol (PDP) type.
 37. The system of claim 36 wherein the PDPtype is represented by two bits “00” indicating that the networksupports IP version
 4. 38. The system of claim 36 wherein the PDP typeis represented by two bits “01” indicating that the network supports IPversion
 6. 39. The system of claim 36 wherein the PDP type isrepresented by two bits “10” indicating that the network supports bothIP version 4 and IP version
 6. 40. A wireless communication system fordetermining whether attach procedures should be implemented based oninternet protocol (IP) version compatibility, the system comprising: (a)at least one wireless transmit/receive unit (WTRU) which supports afirst IP version; and (b) a first network which supports a second IPversion, wherein the first network receives a first attach requestmessage from the WTRU which indicates the first IP version and, if thefirst and second IP versions are determined by the first network to becompatible, proceeding with the attach procedures to establish acommunication link between the first network and the WTRU.
 41. Thesystem of claim 40 wherein the first network includes a serving generalpacket radio service (GPRS) support node (SGSN).
 42. The system of claim40 further comprising: (c) a second network which supports a third IPversion, wherein if the first and second IP versions are determined bythe first network not to be compatible, the second network receives asecond attach request message from the WTRU which indicates the first IPversion and, if the first and third IP versions are determined by thesecond network to be compatible, proceeding with the attach proceduresto establish a communication link between the second network and theWTRU.
 43. The system of claim 42 wherein the second network is a publicland mobile network (PLMN).
 44. The system of claim 42 wherein the firstnetwork directs the WTRU to attempt to establish a communication linkwith the second network.
 45. The system of claim 40 wherein the firstattach request message includes a field having a packet data protocol(PDP) type.
 46. The system of claim 45 wherein the PDP type isrepresented by two bits “00” indicating that the network supports IPversion
 4. 47. The system of claim 45 wherein the PDP type isrepresented by two bits “01” indicating that the network supports IPversion
 6. 48. The system of claim 45 wherein the PDP type isrepresented by two bits “10” indicating that the network supports bothIP version 4 and IP version
 6. 49. The system of claim 42 wherein thesecond attach request message includes a field having a packet dataprotocol (PDP) type.
 50. The system of claim 49 wherein the PDP type isrepresented by two bits “00” indicating that the network supports IPversion
 4. 51. The system of claim 49 wherein the PDP type isrepresented by two bits “01” indicating that the network supports IPversion
 6. 52. The system of claim 49 wherein the PDP type isrepresented by two bits “10” indicating that the network supports bothIP version 4 and IP version
 6. 53. A wireless transmit/receive unit(WTRU) comprising: (a) an antenna; (b) a receiver electrically coupledto the antenna, the receiver for scanning a control channel via theantenna, monitoring a first broadcast channel in the control channel,and receiving a first network compatibility message from a first networkover the first broadcast channel; (c) a memory for storing informationindicating an internet protocol (IP) version supported by the WTRU; (d)a processor electrically coupled to the receiver and the memory forcomparing an IP version field in the first network compatibility messagewith the information stored in the memory; and (e) a transmitter forimplementing attach procedures with the first network when the processordetermines that the IP versions supported by the first network and theWTRU are compatible.
 54. The WTRU of claim 53 wherein if the IP versionsof the first network and the WTRU are determined by the processor not tobe compatible, the receiver monitors a second broadcast channel in thecontrol channel and receives a second network compatibility message fromthe second network over the second broadcast channel, and thetransmitter implements attach procedures with the second network if theprocessor determines that the IP versions supported by the secondnetwork and the WTRU are compatible.
 55. An integrated circuit (IC) incommunication with an antenna, the IC comprising: (a) a receiverelectrically coupled to the antenna, the receiver for scanning a controlchannel via the antenna, monitoring a first broadcast channel in thecontrol channel, and receiving a first network compatibility messagefrom a first network over the first broadcast channel; (b) a memory forstoring information indicating an internet protocol (IP) versionsupported by the IC; (c) a processor electrically coupled to thereceiver and the memory for comparing an IP version field in the firstnetwork compatibility message with the information stored in the memory;and (d) a transmitter for implementing attach procedures with the firstnetwork when the processor determines that the IP versions supported bythe first network and the IC are compatible.
 56. The IC of claim 55wherein if the IP versions of the first network and the IC aredetermined by the processor not to be compatible, the receiver monitorsa second broadcast channel in the control channel and receives a secondnetwork compatibility message from the second network over the secondbroadcast channel, and the transmitter implements attach procedures withthe second network if the processor determines that the IP versionssupported by the second network and the IC are compatible.
 57. A Node-Bcomprising: (a) an antenna; (b) a receiver electrically coupled to theantenna for receiving an attach request message from a wirelesstransmit/receive unit (WTRU); (c) a memory for storing informationindicating an internet protocol (IP) version supported by the Node-B;(d) a processor electrically coupled to the receiver and the memory forcomparing an IP version field in the attach request message with theinformation stored in the memory; and (e) a transmitter for implementingattach procedures with the WTRU when the processor determines that theIP versions supported by the Node-B and the WTRU are compatible.
 58. TheNode-B of claim 57 wherein if the IP versions of the Node-B and the WTRUare determined by the processor not to be compatible, the transmittersends a message to the WTRU indicating that the attach request has beendenied.
 59. An integrated circuit (IC) in communication with an antenna,the IC comprising: (a) a receiver electrically coupled to the antennafor receiving an attach request message from a wireless transmit/receiveunit (WTRU); (b) a memory for storing information indicating an internetprotocol (IP) version supported by the Node-B; (c) a processorelectrically coupled to the receiver and the memory for comparing an IPversion field in the attach request message with the information storedin the memory; and (d) a transmitter for implementing attach procedureswith the WTRU when the processor determines that the IP versionssupported by the IC and the WTRU are compatible.
 60. The IC of claim 59wherein if the IP versions of the IC and the WTRU are determined by theprocessor not to be compatible, the transmitter sends a message to theWTRU indicating that the attach request has been denied.
 61. A networkcomprising: (a) an antenna; (b) a receiver electrically coupled to theantenna for receiving an attach request message from a wirelesstransmit/receive unit (WTRU); (c) a memory for storing informationindicating an internet protocol (IP) version supported by the network;(d) a processor electrically coupled to the receiver and the memory forcomparing an IP version field in the attach request message with theinformation stored in the memory; and (e) a transmitter for implementingattach procedures with the WTRU when the processor determines that theIP versions supported by the network and the WTRU are compatible. 62.The network of claim 61 wherein if the IP versions of the network andthe WTRU are determined by the processor not to be compatible, thetransmitter sends a message to the WTRU indicating that the attachrequest has been denied.
 63. The network of claim 61 wherein the networkincludes a serving general packet radio service (GPRS) support node(SGSN).
 64. The network of claim 61 wherein the network is a public landmobile network (PLMN).